Signaling system



C, v. LOGWOOU.

SIGNALING SYSTEM.

APPLICATION flLED JUNE I6. 1917. 1,397,432,, ,latented Nov. 15, 1921,

C. V. LOGWOOD.

SIGNALING SYSTEM.

APPLlQATlON FILED JUNE 16, 1917.

Patenwd Nov. 15 192% ,2 SHEETS-SHEET 2.

CHARLES "l7. LOG- 001), OF NEW] YORK, N. Y.

SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Nov. 15,1921.

Application filed June 16, 1917. Serial No. 175,131.

To all whom it may concern:

Be itknown that l, CHARLES V. Loewooo, a citizen of the United States,residing at New York, in the county and State of New York, have made acertain new and useful Invention in Signaling Systems, of which thefollowing is a. specification.

This invention relates to signaling systems. The object of the inventionis to provide a signaling system which is simple in construction andarrangement and efficient in operation. A further object of theinvention is to provide a signaling system particularly adaptedfor usein wireless communications. A further object of the invention is toprovide a circuit arrangement which will operate a signaling 'deviceupon the receipt of received signals. A further object of the inventionis to utilize the arrangement above described for automatic switchingfrom transmitting to receiving system for use in connection withtelephony or telegraphy. Further objects of the invention will appearmore fully hereinafter.

The invention consists substantially in the construction, combination,location, relative. arrangement of parts, and circuit connectionsemployed, all as will be more fully hereinafter set forth as shown bythe accompanying drawing and finally pointed out in the appended claims.

Referring to the drawing Figure 1 is a diagrammatic view of a circuitarrangement embodying my invention.

Fig. 2 is a similar view showing one application ofmy invention whereinautomatic switching from receiving'to transmitting is secured.

The same part is designated by the same reference numeral wherever itoccurs throughout the several views.

Multiple step amplification by means of an audion is now well known inthe art, and it among the special purposes of my present invention toprovide means for paralyzing the last audion of amultiple stepamplification immediately upon the receipt of an incoming signal and toutilize the paralyzation of the last amplifier to operate a relay whichin turn operates a signal device.

Referring to the drawing I show in Fig. 1 the usual receiving systemcomprising an antenna 1 connected to earth 9- through the usualinductance 3 and capacity 4.. The re i-cived signals are led to thefirst audion 5 of the multiple step amplifier to the input gridelectrode 6 thereof through the usual transformer well known in the art.The audion 5 delivers to the second step amplifier audion 7 which inturn delivers to the third step audion 8 through the usual circuits wellknown in the art. The respective filaments 9 of the audions areconnected in common to source of current 10 to be heated thereby. Theimpulses received by audion 5 are transmitted fromthe plate electrode 11to the regulation second step amplifier transformer 12 to the gridelectrode 6 of the audion 7, and likewise the plate electrode 11 of theaudion 7 transmits its amplified impulses to the transformer 13, whichis a special transformer preferably one having an iron corethree-quarters of an inch in diameter and four inches long ofapproximately 4,000 turns of number 36 copper wire wound the full lengthof the core, constituting the primary coil. The secondary coilpreferably has two sections, each section of approximately one andone-half inches in diameter and one and one-half inches in length,surrounding the primary winding. The secondary coil preferably has about30,000 turns and preferably of No. 4:0 enamel wire. The amplifiedimpulses transmitted from the second step audion 7 to the transformer 13are received by the grid 6 of audion 8. The secondary of coil 12 feedinginto the audion 7 .is preferably open circuited, while the secondary ofcoil 13 is preferably connected to the common lead of filament 9 througha condenser 14. Connected between the primary of the transformer 12 andthe common lead of the filaments 9 is a source of current such as thebattery 15, so connected that the positive terminal is connected to theplate 11. Likewise a battery 16 is connected between the primary coil oftransformer 13 and the common lead of the filaments 9 so that itspositive pole is connected to the plate 11 of audion 7. Likewise abattery 17 is connected between the plate 11 of audion 8 and thefilaments of the respective audions 5, 7, and 8. A 'resistance 18,preferably variable as shown, is connected between the grid 6 and thefilament 9 of the third step audion 8 which forms a leak for leading ofithe negative change from the grid. 6 of that audion. The amount ofcurrent supplied to the respective filaments 9 from the source 10 iscontrolled by the resistances 19 as is well known.

it is well known in three step amplifica- .tion when the slightestimpulse enters the first step audion the third step will paralyze sothat it is impracticable to use this system of three step amplificationas an amplifier of pulsating current of any strength unless a leak pathis provided so that the negative charge on the grid electrode of thelast amlifier can be led from the grid electrode.

t is the common practice to provide leak paths from the grid in both thesecond and third step amplifiers solely for this purpose. Whereheretofore the paralyzing of the audion of the last step ofamplification has been deemed to have disadvantages and etforts havebeen made extensively to overcome the same, it is among the specialpurposes of my present invention to utilize the paralyzing of the laststep amplifier to perform useful work, such for example as a callingdevice which will call an operator immediately upon the receipt of thefirst signal. It is obvious that normally current flows through the wingcircuit of audion 8 and through the relay 20 back to the filament, butany slight impulse relayed from the transformer 21 of the first stepaudion 5 will paralyze audion 8 and prevent this current flow. Inthis'instance the relay 20, which in the form shown and merely for thepurpose of illustration, I show as a polarized relay, operates tocgntrol an auxiliary circuit, and it is solely for this purpose, namelof increasing the charge on the grid of au ion 8 to paralyze the audionthat the specially constructed transformer 13 is employed, but it isobvious that a specially constructed transformer is not necessary and myinvention therefore is not to be limited thereto. The operation of thesystem is exceedingly simple, signals are received by antenna 1, and aretransmitted through t ansformer 3 to the detector, which, purely for thepurposes of illustration I show in tlfi form of a crystal detector 23,and are thence transmitted through'transformer 21 to the nultiple stepamplifier whereby the received signal is amplified through itsrespective steps many times and a negative charge of considerablemagnitude is thrown on the grid 6 of audion 8, thereby causing currentto stop flowing through the polarized relay 20 to operate the arm 25 andclose the circuit of any signaling device, such for example as a bell-26fed from current source such'as a battery 27. -Consequently it will beseen that. immediately upon the receipt of a'signal'the paralyzing ofthe last step audion'operates to supplycurrent to a relay to operate thesame to render operative a si rial-indicating device.

. ith but slight modification this inven- "tion can be utilized toautomatically switch a transmitting circuit to a receiving circuit, andfor this purpose I have shown one application ofmy invention to such anarrangement in Fig. 2. In this instance I employ "the. antenna 29connected to the earth 30 through the capacity 31 and inductance 32 forthe transmitting circuit, and the antenna 29 connected to the earth 33through inductance 34 for the receiving circuit. The antenna 29 isautomatically switched between the two circuits 32, 31, 30 and 34, 33 bythe action of a relay 35 and armature 36, which relay 35 is controlledby the circuit which in turn is controlled by the paralyzing of the laststep audion 8. A microphone transmitter 37 fed from the source such asbattery 38 leads to the transformer 39 which feeds to the transformer 40of the first step audion 5 and the signals thus received are deliveredto the audion 7 and from there to the audion 8 in the usual and wellknown manner, all as has been hereinbefore de scribed. The high negativecharge on the grid of audion 8 causes the polarized relay 20 to operateto open the normally closed circuit of battery 41 relay 42 and thence toreturn through the armature 43 controlled by the polarized relay, andlikewise the circuit controlling the relay 35. The opening of thiscircuit deenergizes the relay 42 and allows its armature 45 to establishthe circuit between the contacts 46 and 47. Likewise the deenergizing ofthe magnet 35 allows its armature 36 to establish circuit connectionwith the sending antenna system 32, 30. At the same time the soundcurrents generated by a microphone 37 are transmitted through the coil50 to the, grid of audion 100 51 which isincluded in the circuit of theusual audion transmitting system 52 which is the usual system employedfor transmission and comprises generally the filament gridandplateelectrodes, the grid and fila- 105 ment electrode being connectedby inductance 53, capacity 54, which inductance 5 is associated withinductance 32 of the antenna earth system. It is seen that the armature36 controls the transmitting circuit and unless circuit connection isestablished between 46 and 47 the oscillion system is inoperative. Thegrid electrode of audion 52 is provided with a leakage path for itsexcessive negative charge to the filament of the audion 51, whichfilament is otherwise completely insulated from the remaining electrodesof the audion. In other words the receivedrimpulses transmitted to theaudion 51 from coil 50 control the os- 12C cillating circuit of audion52 in accordance with the degree of leak from the grid of audion 52.This is accomplished by controlling and neutralizing the positive andnegative charges in the audion 51 by the voice as Wlll be readilyunderstood. When the operator ceases to speak into the microphone 37 theparalyzed condition of audion 8 disappears, thereby allowing thepolarized relay 20 to close the circuit of the respective V operatorceases to speak before the system.

spealrin menace relays l2 and 35 which is the one instance operates toopen the transmitting circuit, and in the other instance to switch thean tenna to its receiving circuit. This is the normal condition of theapparatus and its normal condition is retained until signals are againsent in the transmitter 87.

The leak path formed by the varied resistance 18 connected between thegrid and filament of the audion 8 serves the purpose of allowing thehigh charge on the grid to leak therefrom when the operator ceases inthe traninitte'r, and this again places't e audion in normal condition.By varying this resistance, or rather by adjusting it, the paral zedcondition of the audion can be control ed at will with respect to thelength of time it remains paralyzed. Thus it can be readily adjusted toallow say from five to ten second to lapse after the will be switchedautomatically to the reoeiving circuit. Likewise it can be adjusted toact almost instantly upon the completion of an expression or clause. Itis obvious, however, that any desired control may be thus effected. 1

It is obvious that while I have shown this system as an automaticswitching arrangement in connection with, radio telephony my inventionis not to be limited or restricted thereto, as with but slightmodification ap' parent to one skilled in the art the radio telegraphsystem may be employed. 1 have not shown the receiving system but merelythe traniormer 34- leading to the same as any receivin system well knownin the art may be cmp oyed, but

Having now set forth the objects and na ture of my invention, what Iclaim as new and useful, and of my own invention, and desire to secureby Letters Patent, is,

l. The combination with a receiving circuit and transmitting circuit,provided with a common antenna, a switch normally connecting saidantenna to said receiving circuit, a relay controlling said switch, anandion, a s gnaling device associated with said audiona id with saidtransmitting circuit, means actuated by the operation of said gggsignaling device for paralyzing said audion, and mean operated therebyfor actuating said relay to operate said switch.

2. The combination with a receiving circuit and a transmitting circuit,provided with a common antenna, a switch normally connecting saidantenna to said receiving circuit, a relay controlling said switch, anaudion, a signaling device associated with said audion and with saidtransmitting circuit, means actuated by the operation of said signalingdevice for impressing a large negative charge on the grid electrode ofsaid audion, and means operated thereby for actuating said relay tooperate said switch.

3. in an automatic signaling system, an antenna normally in circuitrelation with a receiving system, a normally open-circuited transmittingsystem, a source of sig nals, an audion associated therewith, and meancontrolled by said source of signals for impressing a large negativecharge on the grid electrode of said audion, and means operated therebyfor closing the transmit tin circuit and connecting the antenna to saidtransmitting system.

4. in an automatic signaling system, an antenna normally in circuitrelation with a receiving system, a normally open-circuited transmittingsystem, a source of signals, an audion associated therewith, and meanscontrolled by said source of signals for paralyzing said audion, andmeans operated thereby for closing the transmitting circuit andconnecting the antenna to said. transmitting system.

5. The combination with an antenna, of a receiving system and atransmitting system associated therewith, one of said systems beingnormally connected to said antenna, an audion, means controlled by theparalyzing oi the audiontor automatically connecting said antenna to theother oi said systems and. simultaneously breaking the connectionbetween said antenna and the system normally connected thereto.

in testimony whereof I have hereunto set my hand on this oist day of MayA D, 1917.

